I think I am having a problem with the proximity sensor (sprint tp2). When I place or answer an incoming call the screen turns off. It can not be turned back on. Pressing the power button during the call will not turn it back on. Even after the call ends (other party hangs up) screen still can not be turned on by pressing the power button. Sliding the keyboard will turn the screen on in-call or after call. Power button will turn on the screen as expected until the next call is made or answered. Is there a way to force screen on power button?
I don't see this in WinMo but I have noticed that each time I make a call while phone is in upright position the screen will turnoff for a second then it comes back on.
Do you use a protective case? I had a very similar issue and I was able to resolve it by taking the case off (and drilling a hole in the protective case where the proximity sensor was placed). There are 2 possible positions for the sensor (on the left or right side of the phone by the ear piece depending on your model... Sprint's sensor should be on the left side). If you are not using a protective case, then I would follow the other excellent advice.